Convert AAC to OPUS

Tested on Windows 11, 24 October 2026

Convert AAC audio to OPUS in your browser or in the Filoshi app for Windows. OPUS is lossy: Filoshi uses a high-quality setting, and you can choose the bitrate. Nothing is uploaded.

Get Filoshi · $29Many files at once, no size limit, on Windows.

How to convert AAC to OPUS in your browser

  1. 1
    Drop your AAC file
    Drag it onto Filoshi above, or press Choose your AAC file to pick it on your computer.
  2. 2
    Filoshi converts it
    OPUS is chosen already. FFmpeg, compiled to WebAssembly, converts it inside this browser tab.
  3. 3
    Save your OPUS file
    Download it when it is ready. Nothing was sent to a server.
Source format

What is AAC?

Advanced Audio Coding (.aac). AAC is the lossy codec designed to replace MP3, with better sound at the same bitrate. It is the audio of most MP4 videos, YouTube and Apple devices. Raw .aac files are a bare AAC stream without the M4A container.

Common use: Streaming, the sound track of MP4 video, Apple devices

Output format

What is OPUS?

Opus Audio (.opus). Opus is an open, royalty-free codec standardised by the IETF in 2012. It sounds very good at low bitrates for both speech and music, and it is the codec of WebRTC video calls and many voice-message apps.

Common use: Voice messages, calls, streaming, podcasts

Questions about AAC to OPUS

Is converting AAC to OPUS free?
Yes, one file at a time: the converter on this page runs in your browser, files up to 100 MB, no sign-up. The Filoshi desktop app ($29 once, for Windows) converts many files at once and has no size limit.
Does converting AAC to OPUS lose quality?
Yes, a little. OPUS is a lossy format, so some detail is thrown away when the file is saved. Filoshi uses a high-quality setting by default, and you can choose the bitrate in the file viewer. AAC is lossy too, so this is a second round of compression; convert from the original, not from earlier conversions.
Is my AAC file uploaded anywhere?
No. The converter on this page runs in your browser with FFmpeg compiled to WebAssembly; your AAC file is read and converted on your device and never sent to a server. The desktop app works the same way, offline.
Has AAC to OPUS been tested?
Yes. AAC to OPUS is one of the 1,841 conversions that passed Filoshi's automated test matrix on Windows 11.
Can I convert many AAC files at once?
Yes, in the desktop app. Drop as many AAC files as you like on the window, pick OPUS once for all of them, and each file shows its own progress. The new files appear next to the originals, which are never changed.

Related conversions

Other AAC conversions

AAC to MP3AAC to OGGAAC to FLACAAC to M4AAAC to AIFFAAC to AC3AAC to AUAAC to CAF

Convert to OPUS

MP3 to OPUSWAV to OPUSOGG to OPUSFLAC to OPUSM4A to OPUSWMA to OPUSAIFF to OPUSALAC to OPUS

Need AAC to OPUS for many files?

The browser converter handles one file at a time. The Filoshi app for Windows converts as many as you drop, runs offline, and has 1,841 tested conversions.

Get Filoshi · $29